We have not inherited the Earth from our fathers. We are borrowing it from our children.

—Native American saying

Photographs from outer space impress on the world that humankind shares one planet, and a small one at that. (See Figure 1.1.) Earth is one ecosystem. There may be differences in race, nationality, religion, and language, but everyone resides on the same orbiting planet.

General concern about the environment is a relatively recent phenomenon. Two closely related factors explain the rising concern during the second half of the twentieth century: global industrialization following World War II and the worldwide population explosion. It was once thought that the life-sustaining resources of planet Earth were infinite; now it is known that these resources are finite and limited.

Historical Attitudes Toward the Environment

The Industrial Revolution

Humankind has always...